⚡ FREE · NO SIGNUP · GPS · GLONASS · GALILEO · BEIDOU

GNSS Mission Planner

Plan your field session before you leave the office. Multi-constellation satellite visibility, DOP charts, and best-window recommendation — free, no signup, all browsers.

Drag the time-of-day, watch the sky fill or empty. Yellow band in PDOP chart = under 3 is good for most field work. Green band on the sat-count chart = the optimal 2h window we found for you.

💡 Pro tip: 2 hours before the predicted best window, dispatch the field crew so they hit the road and arrive at the site exactly when PDOP drops.

Frequently Asked Questions

Where does the orbit data come from?

Two-Line Element sets (TLE) from CelesTrak.org, the public NORAD-derived feed. We refresh every 6 hours. Propagation uses the standard SGP4 model (satellite.js library).

Why do my numbers slightly differ from Trimble Planning?

TLE sets are revised regularly, so two planners snapping different TLE revisions disagree at the sub-second / sub-arcminute level — irrelevant for field planning. Mask angle and how unhealthy satellites are filtered also matter.

Can I use this on my phone in the field?

Yes — the planner is fully responsive. The "Use my location" button works on most modern phones and tablets.

Is the planner accurate enough for RTK / static / kinematic planning?

Yes, for typical surveying / RTK pre-field planning. For precise satellite engineering (e.g. orbit determination) use IGS final products instead.

Learn more
Read the surveyor's guide to mission planning
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